Snakes and canids (dogs) were presumed to be intermediate hosts of SARS-CoV-2 based on sequence analysis of the relative synonymous codon usage (RSCU) bias between SARS-CoV-2 and animal host species [227] and based on analysis of zinc finger antiviral protein (ZAP) expression in animal host species and tissues that drive CoV evolution to have a low-CpG (5′-Cytosin-phosphate-Guanine-3′) viral genome [228], respectively.